Early-life menstrual characteristics and gestational diabetes in a large US cohort.

Background: Associations between early-life menstrual cycle characteristics (MCC) and gestational diabetes (GDM) remain unclear.

Objectives: To evaluate associations between early-life MCCs and GDM in first pregnancy, across pregnancies and its recurrence.

Methods: This analysis included participants from a US-based digital cohort enrolled between 11/2019 and 9/2023 who provided consent, completed relevant surveys, were without diabetes and aged ≥18 at first pregnancy (n = 30,473).

Daily snuff use during pregnancy, gestational length and birth weight; register-based study.

Background: Snuff is a smokeless source of nicotine that is common in Scandinavia and increasingly used by women of fertile age. Persistent use of snuff during pregnancy has been associated with adverse pregnancy outcomes. Emerging data from the Medical Birth Registry of Norway distinguishes between occasional use and daily use.

Racial and Ethnic Disparities in Phthalate Exposure and Preterm Birth: A Pooled Study of Sixteen U.S. Cohorts.

Background: Phthalate exposures are ubiquitous during pregnancy and may contribute to racial and ethnic disparities in preterm birth.

Objectives: We investigated race and ethnicity in the relationship between biomarkers of phthalate exposure and preterm birth by examining: ) how hypothetical reductions in racial and ethnic disparities in phthalate metabolites might reduce the probability of preterm birth; and ) exposure-response models stratified by race and ethnicity.

Methods: We pooled individual-level data on 6,045 pregnancies from 16 U.

Urinary Paraben Concentrations and Associations with the Periconceptional Urinary Metabolome: Untargeted and Targeted Metabolomics Analyses of Participants from the Early Pregnancy Study.

Background: Parabens, found in everyday items from personal care products to foods, are chemicals with endocrine-disrupting activity, which has been shown to influence reproductive function.

Objectives: This study investigated whether urinary concentrations of methylparaben, propylparaben, or butylparaben were associated with the urinary metabolome during the periconceptional period, a critical window for female reproductive function. Changes to the periconceptional urinary metabolome could provide insights into the mechanisms by which parabens could impact fertility.

Birthweight of the subsequent singleton pregnancy following a first twin or singleton pregnancy.

Introduction: Birthweight is an important pregnancy indicator strongly associated with infant, child, and later adult life health. Previous studies have found that second-born babies are, on average, heavier than first-born babies, indicating an independent effect of parity on birthweight. Existing data are mostly based on singleton pregnancies and do not consider higher order pregnancies.

Large-Scale Data Harmonization Across Prospective Studies.

The Preconception Period Analysis of Risks and Exposures Influencing Health and Development (PrePARED) Consortium creates a novel resource for addressing preconception health by merging data from numerous cohort studies. In this paper, we describe our data harmonization methods and results. Individual-level data from 12 prospective studies were pooled.

Inferring fetal growth restriction as rare, severe, and stable over time.

Reduced birthweight is a marker of pathologies that impair growth and also decrease survival. However, "fetal growth restriction" remains poorly defined. Assuming that birthweight itself has no causal effect on neonatal mortality, we can estimate the features of pathological fetal growth that would be required to produce the observed pattern of weight-specific mortality.

Reproductive outcomes in women and men conceived by assisted reproductive technologies in Norway: prospective registry based study.

Objectives: To determine whether the perinatal outcomes of women or men who were conceived by assisted reproductive technologies are different compared with their peers who were naturally conceived.

Design: Prospective registry based study.

Setting: Medical Birth Registry of Norway.

Invited Commentary: Beyond Barker-Mothers Are the Ones at Risk.

Dr. David Barker hypothesized that low birth weight (LBW) is the result of inadequate fetal nutrition, leading to increased risk of cardiovascular disease (CVD) in the offspring. This hypothesis has stimulated thousands of reports on low birth weight (LBW) and CVD risk.

Urinary phenol concentrations and fecundability and early pregnancy loss.

Study Question: Are urinary phenol concentrations of methylparaben, propylparaben, butylparaben, triclosan, benzophenone-3, 2,4-dichlorophenol or 2,5-dichlorophenol associated with fecundability and early pregnancy loss?

Summary Answer: 2,5-dichlorophenol concentrations were associated with an increased odds of early pregnancy loss, and higher concentrations of butylparaben and triclosan were associated with an increase in fecundability.

What Is Known Already: Phenols are chemicals with endocrine-disrupting potential found in everyday products. Despite plausible mechanisms of phenol reproductive toxicity, there are inconsistent results across few epidemiologic studies examining phenol exposure and reproductive function in non-fertility treatment populations.

Associations Between Prenatal Urinary Biomarkers of Phthalate Exposure and Preterm Birth: A Pooled Study of 16 US Cohorts.

Importance: Phthalate exposure is widespread among pregnant women and may be a risk factor for preterm birth.

Objective: To investigate the prospective association between urinary biomarkers of phthalates in pregnancy and preterm birth among individuals living in the US.

Design, Setting, And Participants: Individual-level data were pooled from 16 preconception and pregnancy studies conducted in the US.

Parental fecundability and neurodevelopmental delays and difficulties in offspring.

Background: Impaired neurodevelopment is reported among children conceived by assisted reproductive technologies (ART). However, this might be explained by conditions underlying parental subfecundity, rather than the ART procedure.

Methods: We examined associations of parental time-to-pregnancy (TTP) and conception by ART with neurodevelopmental traits up to 8 years of age, including motor and language skills, social delays and difficulties, and inattention-hyperactivity, among 92 142 singletons participating in the Norwegian Mother, Father and Child Cohort Study (MoBa).

Glycated haemoglobin (HbA1c) in mid-pregnancy and perinatal outcomes.

Background: Maternal diabetes is a well-known risk factor for pregnancy complications. Possible links between long-term maternal blood sugar in the normal range and pregnancy complications are less well described.

Methods: We assayed glycated haemoglobin (HbA1c) in blood samples collected around the 18th week of pregnancy for 2937 singleton pregnancies in the Norwegian Mother, Father and Child Cohort Study (2000-09).

Menstrual irregularity as a biological limit to early pregnancy awareness.

US state legislatures have proposed laws to prohibit abortion once the earliest embryonic electrical activity is detectable (fetal "heartbeat"). On average, this occurs roughly 6 wk after the last menstrual period. To be eligible for abortion, people must recognize pregnancy very early in gestation.

The association between miscarriage and fecundability: the Norwegian Mother, Father and Child Cohort Study.

Study Question: Is fecundability associated with miscarriage history and future miscarriage risk?

Summary Answer: Prior miscarriage was associated with lower fecundability, and participants with a history of subfertility (time-to-pregnancy (TTP) ≥12 months) were at a higher risk of subsequent miscarriage.

What Is Known Already: Although miscarriage and low fecundability share common risk factors, prior studies have reported both lower and higher fecundability after miscarriage.

Study Design, Size, Duration: In this study, we examined two related associations: one, between miscarriage history and subsequent fecundability and, two, between fecundability and miscarriage risk in the subsequent pregnancy.

Maternal intake of folate during pregnancy and risk of cerebral palsy in the MOBAND-CP cohort.

Background: Folate prevents neural tube defects and may play a role in some neurodevelopmental disorders.

Objectives: We investigated whether higher intakes of periconceptional or midpregnancy folate, as recommended, were associated with a reduced risk of offspring cerebral palsy (CP).

Methods: We included participants from the Nordic collaboration cohort consisting of mother-child dyads in the Danish National Birth Cohort and the Norwegian Mother, Father, and Child Cohort Study [combined as MOthers and BAbies in Norway and Denmark (MOBAND-CP)].